Related Applications
There are no applications related hereto heretofore filed in this or any foreign country.
Field of Invention
The instant invention relates generally to ventilators that extract fumes from work stations such as welding sites and more particularly to such devices that are portable for field work especially such as welding sites on or about railroad tracks in place.
Background and Description of Prior Art
Various industrial processes generate deleterious fumes, which must be dealt with to protect workers in or at the sites of the processes. Welding processes present particular problems of this type because the high temperatures involved and various materials used in the process such as fluxes, oxidation inhibiting agents and the like produce gaseous by-products that may be injurious to the health of workers at or about a welding site. The problem has long been recognized and in the present day has become sufficiently significant that various governmental authorities have been established to oversee and regulate the problem.
In established permanent industrial areas where welding is carried out fumes can be controlled by relatively permanent and sophisticated mechanisms that remove the deleterious fumes from the area for replacement by ambient atmosphere or process the fumes to remove or at least attenuate their environmentally adverse impact. Dealing with fumes in on-sight field type welding operations, however, is quite different and creates more complex problems. For field use, ventilator or fume extractor systems must have portability and generally may not have complex or overly sophisticated apparatus or processes to modify the deleterious products exhausted by the systems.
Portable ventilator systems for field use at welding sites on or about railroad tracks present additional problems by reason of the environment in which they are used and though ventilators have heretofore become known for such purpose various problems still remain with such systems. The instant ventilator seeks to resolve various of these remaining problems while yet providing a ventilator which may well and effectively be used in other environments requiring use of such a device.
Railroads for safety purposes have long used electric current carried by the opposed metallic rails of a track system to indicate the presence or absence of one or more trains within portions of the track system by providing signaling devices operated by a low amperage, relatively low voltage, direct current circuit carried through various adjacent portions of the track system known as “blocks”. A plurality of blocks is sequentially interconnected with adjoining blocks in series type electrical interconnection to form an “interlocking closed track system”. The electric current in each block operates signaling devices along its track forming the electric circuit in the block and transmits data indicating block condition to distant control operations and trains using the interlocking closed track system.
In a modern interlocking closed track system, a power supply is located at one end of a block and a relay is located at the other end of the block. A train entering the block shorts both the relay and the power supply with its steel wheels and interconnecting axles to cause the relay to open to responsively indicate that the block is occupied by a train or similar rail vehicle. Failure of any component in the system breaks the circuit to indicate that the block is occupied to provide a fail-safe system stopping further traffic until the failure is corrected.
In modern track systems rails are formed of electrically conductive steel and usually have substantial lengths of one-quarter to one-half mile or possibly more. A plurality of rail segments are commonly welded together at their adjoining ends to form continuous tracks of any desired length. If the adjoining rail ends are not welded, and in some instances even where they are welded, the track ends are electrically connected to each another by copper straps and fasteners collectively called “bonds” to ensure electrical conductivity. One end of each copper strap commonly is secured to one end of each adjoined rail by bolting.
In maintaining track systems it is often necessary to weld on the system rails while the block signal system associated with the rails is operative. Typically rail welding is accomplished by an electrical arc, which uses high amperage current at a medial voltage that is transmitted through one rail to a welding electrode nearby to institute the welding arc. During this process if the rail carrying the high amperage welding current is inadvertently shorted to the opposed rail, the welding current may be transmitted through the block signal circuitry to cause catastrophic damage to the low voltage low, amperage signaling system which can be expensive to repair or replace and cause a shutdown of the particular block or possibly the entire interlocking closed track circuit until repairs are made. By reason of this problem a ventilator used about track system welding sites to be practically operative must provide some means or method for preventing the extractor from being the instrumentality by which shorting between rails might accidentally occur. In the instant ventilator, which is of an elongate nature with length that may be sufficient to extend between two opposed rails of a track, it has been found that most if not all of the device may be formed of electrically non-conductive plastic material arranged in such fashion in relation to conductive material as to prevent the passage of any electric current through the ventilator or between adjacent rails.
Welding processes in general and particularly electric arc welding, use fluxes of various sorts which when heated to welding temperatures form substantial quantities of gasses which may be quite deleterious to human health and must therefore be moved away from workmen in the area of a welding site for worker safety and to comply with various governmental, employment and health regulations. The most common method of protecting such workmen in the past, and especially the welder, has been to use semi-enclosed welding helmets having an associated eye protecting device and a ventilating system. The known welding helmets, however, do not adequately resolve the ventilating problem as firstly, the deleterious gasses may be brought into the containment space about the head of a welder and may cause substantial worker damage before exhaustion. Secondly, depending upon the area of exhaustion of the gasses from the helmet, the exhausted gasses may re-enter the helmet space. Such welding helmets also generally do not protect any workers in the welding area except the welder. Ventilated welding helmets also are expensive, increase the mass of the helmet, and make it more uncomfortable for use by a worker. Commonly welding helmets with ventilating systems are operated by an electrically powered fan type device, but in field areas electrical power may be unavailable or difficult to obtain in commonly required current ranges.
My ventilator resolves various of these problems by providing a device of an elongate tubular nature having a metallic funnel-like input structure carried by an elongate plastic exhaust pipe which is electrically non-conductive to allow slag and metal particles that may be thermally active to be received in the metallic input structure while exhausting deleterious gaseous material through the output orifice distant from the welding site without any possibility of the device creating an electrically conductive path between the opposed rails of a track system. The ventilator is powered by introducing a stream of high-pressure air into the radially medial portion of the exhaust channel at or spacedly near the joinder of the exhaust pipe with the input structure. Pressurized air is used to power the ventilator as a source of pressurized air is available at most welding sites, and especially railway welding sites, to power other tools there used. Use of pressurized air for such powering eliminates the possibility of electrical shorting between the rails of a block signal system by accidents involving current from an electrically powered fan and eliminates the potentiality of additional contamination about a welding site such as may result from fossil fuel powered motors that may be required to directly or indirectly power a fan type device. The use of pressurized air also allows direct powering of the ventilator mechanism without additional apparatus such as fans, turbines or the like that would be required to move gasses and requires no moving parts that wear or require maintenance.
My ventilator provides a sturdy compact light weight device that may be readily manually manipulated by a workman for proper positioning and orientation to disperse deleterious gasses from an open field welding site at a distance from the site and in an orientation consistent with local prevailing winds for effective removal from the welding site and from about the welder. The ventilator is also sufficiently manipulable and has high enough air flow therethrough that it may be oriented with its output end adjacent a welding site to blow ash, slag, metallic particles and similar smaller debris from about the welding site when necessary.
Various devices to remove welding gasses from a welding site have heretofore become known. These known devices may be divided into a first class having motor driven fan or turbine mechanisms to move welding fumes and a second class, which uses pressurized gas to move the fumes for exhaustion distally from the welding site. Devices of the first class are distinguished from those of the second class by reason of their required motors and air moving mechanisms, both with their inheritant infirmities and which are not required in devices of the second class. The instant ventilator is a member of the second class that resolves problems that have not been resolved by its classmates.
Most members of the second class of ventilators have not been particularly concerned with efficient use of pressurized air to maximize fume extraction. Several devices of the second class have provided exhaust channels formed of flexible tubing having annular accordion type folds orientated perpendicularly to their exhaust channel axis or have introduced pressurized gas adjacent to a tubular surface defining the exhaust channel, either of which tend to increase fluid friction and sometimes even create turbulence or air stream curl in gasses moving through the exhaust channel to lessen the efficiency of its output. The instant invention in contradistinction provides an elongate rigid exhaust tube having a smooth inner surface defining the exhaust channel and introduces pressurized air into the exhaust channel in an axially aligned medial position to establish more uniform flow lines through the channel, minimize gaseous friction adjacent channel walls and decrease curl type turbulence to increase and make more efficient air flow through the exhaust tube, maximize fume extraction and minimize power usage by the device. Additionally, though various known ventilators of the second class have been used for exhausting welding fumes from railway track systems, it appears that none have been directly concerned with the problem of accidentally creating short circuits between the opposed rails of a block of an interlocking closed track system, notwithstanding that such short-circuiting can cause catastrophic results in damaging the system.
Any portable exhaust system to be practically usable must have a length sufficient to waste extracted welding fumes efficiently and remotely from a welding area so that the fumes will not return in any deleterious concentration to the breathing environment of the welding site and such gasses must be dispersed in a direction relative to the welding site position that takes into account localized wind conditions so that exhausted fumes will not be returned to the immediate environment of the welding site by the winds. The instant ventilator resolves this problem by providing a rigid tubular dispersement tube formed of electrically non-conductive material such as polymeric or resinous plastics so that the ventilator may be positioned at a welding site without concern about its position relative to the opposed rails of a track, and may even be supported on and between the opposed rails while the rail being welded upon is carrying a high amperage welding current. The ventilator is light enough to be easily manipulatory for positioning and long enough to exhaust welding fumes at such distance and with such velocity that returns of fumes in any sufficient quantity is unlikely.
My invention does not reside in any of the foregoing features individually but rather in the synergistic combination of all of its structures, which necessarily give, rise to the functions flowing therefrom as herein specified and claimed.